Interpretive Summary: The potato psyllid transmits a bacterium that results in a disease of potato known as zebra chip. The conventional means of control of potato psyllid is with broad spectrum chemical pesticides. Although effective for control, these pesticides kill beneficial insects and have a risk factor for applicators. In an effort to develop alternative methods of control that are safe for the environment and the food supply, ARS scientists at the USDA-ARS laboratory in Wapato, WA and Weslaco, TX and Texas A & M University colleagues evaluated two commercially produced insecticidal fungi for control of potato psyllid in the potato growing area near Weslaco, TX. They demonstrated good insecticidal activity of both products. With additional research on the effects of treatment timing and it’s affects on invading adult psyllids under field conditions, these fungi may permit control of potato psyllid earlier in the growing season without the application of broad spectrum pesticides. Our results indicate that both fungi could be used as environmentally benign components of an integrated strategy for control of potato psyllid.

Technical Abstract:
Laboratory and field trials of the four isolates of entomopathogenic fungi, Isaria fumosorosea and Metarhizium anisopliae were conducted to evaluate their potential for control of the potato psyllid. In the laboratory, 2 ml aqueous suspension of 107conidia/ml in a of each isolate applied in a Potter spray tower provided effective control of adults and nymphs of the psyllid. Maximum mortality of adult potato psyllid occurred 3 days after exposure to I. fumosorosea and M. anisopliae, whereas maximum mortality in nymphs was observed 4 days after exposure. Field trials in Weslaco, TX in 2009 and 2010 were conducted with two commercially produced fungi, I. fumosorosea (Pfr 97, Certis USA) and M. anisopliae (F 52, Novozymes, Biologicals), abamectin (AgriMek, Syngenta) and neem oil (Trilogy, Certis, USA). Each fungus product provided control of nymphs that was comparable to abamectin. Season long control using the recommended concentrations of F 52 and Pfr 97 ranged from 60-78%. Relative to control plots application of both products resulted in improved tuber yield and reduced plant damage.